Chimney top



Oct. 21, 1958 R. K. THULMAN 2,356,837

CHIMNEY TOP Filed June 10, 1955 2 Sheets-Sheet 1 ATTORNEY Oct. 21, 1958R. K. THULMAN' 2,856,837

CHIMNEY TOP Filed June 10, 1955 2 Sheets-Sheet 2 5 7 5 a L a g 66 222566 \SZQQ W N 1' 30 4 I II 661 4% a9 5 a e INVENTOR ATTORNEY UnitedStates Patent Ofiice 2,856,837 Patented Oct. 21, 1958 CHIMNEY TOP RobertK. Thulman, Silver Spring, Md. Application June 10, 1955, Serial No.514,586

9 Claims. (Cl. 98-46) This invention relates to the art of chimneyconstruction and more particularly to a chimney top. The invention maybe most conveniently employed in conjunction with a chimney of the typedescribed and claimed in my prior Patent No. 2,634,720, issued April 14,1953, for Chimney Construction With Heat Tranfer Controlling Means, butthe principles of the invention are applicable to other chimneys aswell. in Fig. 1 of my aforesaid patent a chimney is described whichincludes a central flue and a pair of concentric thermosyphon aircirculation ducts ararnged about the flue, the flue and ductscommunicating with the atmosphere at their upper ends in such a way thatthe draft in the flue does not cause aspiration of air through theducts, there being a housing enclosing the upper ends of the ducts forpreventing rain from entering the same, and within which 'said ductscommunicate with the atmosphere, this arrangement providing for partialrecirculation of the air if desired.

Chimneys of the prior art are subject to many defects, among which arethe difiiculty of preventing rain from entering the flue withoutinterference with proper action of the chimney. While there are rain capdevices in the prior art which have been reasonably successful inpreventing rain from entering the flue, such devices are generallyunsightly and interfere with the free flow of flue gases. Moreover,because such devices are placed in the path of the flue gases, soot andash deposits collect upon them, and when it rains, these deposits arecarried down the outer sides of the chimney, causing ugly stains.

It is a principal object of the present invention to obviate defects ofthe prior art by preventing rain from entering the flue of the chimneyand by avoiding soot and ash stains at the top of the chimney, whilestill providing a relatively free path for the flow of flue gases. Whenemployed in conjunction with the chimney of my aforesaid prior patent,the invention also prevents rain, soot and ash from entering theconcentric ducts and provides for the free interchange of air betweenthe ducts and preferably for the ventilation of the space below theroof. The unique chimney top of the present invention is not onlyfunctional, as indicated above, but also serves as an ornamental housingfor the top of the chimney. In addition, the invention is economical andsimple to construct and install.

Briefly, the foregoing objects of the invention are accomplished byproviding a chimney top including an outer housing, unique baifle means,and a rain cap. The housing is joined to the roof so as to provide awatertight junction and supports the baffle means and rain cap. Suitablepaths areprovided for the flow of flue gases, while the baflle means arearranged to protect the concentric ducts associated with the chimneyfrom rain, soot and ash and in fact to direct rain which enters thehousing so that most of it drips onto the roof but does not run down thesides of the chimney housing.

The foregoing and other objects of the invention will be made morereadily apparent by the following detailed description of anillustrative embodiment of the invention as exemplified in theaccompanying drawings, wherein:

Fig. 1 is a perspective view of the illustrative embodiment, partiallybroken away, as seen in a typical roof top installation;

Fig. 2 is a vertical section thereof taken along line 22 of Fig. 3;

Fig. 3 is a plan view thereof; and

Fig. 4 is a disassembled plan view illustrating an alternative form ofbaflle on a reduced scale.

As shown in Fig. l of the drawings, the chimney may be installed on atypical sloping roof generally designated 10, having a ridge 12, andcomprising suitable sheathing exemplified by wooden planks 14. In thestate of construction illustrated, the final roofing, for example,asphalt or other conventional material, has not been applied. Thechimney top housing 16 is arranged vertically with its lower endtruncated on a plane determined by the slope of the roof (see Figv 2)and supported on flashing members 13, 20, described in more detailhereinafter. Housing 16 has a lower or body portion 17,

and is provided with an upper or cap portion comprising a rain and windshield 22, a rain cap 24, and baffle means 26, 28. In the form shown,the chimney top is employed in conjunction with the chimney of myaforesaid prior patent, which includes a central flue 30, an innercasing 32, and an outer casing 34, and the body portion 17 correspondswith the casing 14 of my prior patent, while the elements 22 and 24perform the function of the cap 15 of my prior patent as well asadditional functions.

Referring more particularly to Fig. 2, in the form shown flue 34comprises an upper section 36 which telescopes into a lower section 38.The bottom end of section 38 may communicate with a heating device, suchas an oil or gas fired furnace or a fireplace. Inner casing 32 is spacedfrom and defines with flue section 38 an inner duct 40, and outer casing34 is spaced from and defines with inner casing 32 an outer duct 42. Theinner duct terminates before the end of flue 30, while the outer ductterminates before the end of the inner duct, and the draft of the fluedoes not aspirate air through theducts. In other words, the ducts aswell as the flue each communicate with the atmosphere at their upperends, since the space Within housing 16 is open to the outside air byvirtue of a lower air passage 44 at the bottom of shield 22 and an upperair passage 45 between the rain cap 24 and the shield as well as by wayof the spaces between baffle 28 and the flue and between baflle 26 andthe wind shield 22, while in the form shown, such housing space is alsoopen to the attic space through the opening at 46 between therectangular flashing 18, 20, and the cylindrical outer casing 34. Theupper portion or cap 22 of housing 16 preferably comprises a skirt 22aextending laterally beyond the lower portion 17, and is spaced from thetop edge of the lower portion so as to define the passage 44. In thepreferred form, only the bottom section or skirt 22a of the shield 22extends beyond the lower housing portion, preferably depending somewhatbelow its upper edges, as shown. The bottom section or skirt 2211 may besurmounted 'by an upper section 2212 that preferably has lateraldimensions substantially the same as lower portion 1.7.

The flue and the ducts 32 and 34 pass through a hole 46 formed or cut inthe roof sheathing 14, and the chimney top housing may be mountedentirely above the roof level, as illustrated in Fig. 2. In the formshown, hole 46 is rectangular and the corresponding hole formed by theflashing members 18, 20 is also rectangular. The flashing members may beformed with upwardly extending collar portions, which may overlap asindicated at 50 when the flashing is installed so as to define a collar48 surrounding hole 46. The fiat portions of the flashing members mayalso overlap as indicated at 52 1n Fig. 1. A typical method ofinstallation will be set forth in detail hereinafter; suffice it to sayfor the present that housing 16 may be supported on the flashing and theroof sheathing by a plurality of angle brackets 54, two of which areillustrated in Fig. 1; shield or cap 22 may be supported on housingportion 17 (as illustratedin Fig. 2) by a plurality of Z-shaped brackets56, which may be riveted or bolted to the upper and lower lionsingportions; and rain cap 24 may be supported on shield 22 by a pluralityof Z-shaped brackets 66, which may be riveted to one of these membersand bolted to the other so that the cap may be readily removed (see alsoFig. l). The top of the shield 22 may be formed with an inwardly turnedlip 63, which cooperates with rain cap 24 in obstructing the entrance ofrain to housing 16, and in the preferred form the upper end of thehousing 16 is formed with a central opening 4'7 constituted by the inneredge of the lip 68, the rain cap 24 being suspended below this openingand above flue 36, with the periphery of the rain cap 24 spaced from lip68 so as to define air passage 45, the lateral dimensions of the capbeing sufficient to ensure shielding of the flue opening.

Bafiies 26 and 28 may be supported in many ways. For example, baffle 26may be riveted or bolted to shield 22, as indicated at 58, and bafiie 28may be suspended from baflie 26 by a plurality of U-shaped brackets 63riveted or bolted to the respective baflies. Alternatively, oradditionally, baffle 28 may be supported by the Z-shaped brackets 56riveted or bolted to the baffle as indicated at 62. Of course, if baffle28 is supported by brackets 56, the rivets or bolts at 523 may beomitted, and baffle 26 may be mounted on bafiie 28 by brackets 60.

Each baffle is preferably formed with a central aperture to receiveupper flue section 36. The aperture in the lower bafile 28 may have asubstantially larger diameter than the outer diameter of section 36 soas to allow air beneath the lower baffle 28 to pass between the baffles.The aperture in the upper baffle 26 may be just large enough toaccommodate flue section 36. The upper flue section 36 may then besupported by suspension in baffle 26 by virtue of an enlarged or flaredend portion 64.

As shown in Figs. 1 and 2, the upper surface of rain cap 24 preferablyslopes downward from its center, and in the form shown has asubstantially pyramidal shape. The upper surface of bafl'les 26 and 28also slope downward from the center, and the upper contours of thebaflles may be substantially alike. The outline of the baffles as seenin plan is preferably polygonal and may be substantially rectangular asshown in Fig. 3, and the batlles are preferably arranged with thecorners of one interposed between the corners of the other, as shown inFigs. 1 and 3. The outline of the lower baffle preferably conformsapproximately to the outline of the enlarged upper housing portion, andthe bafiie extends into this portion with its periphery spaced slightlyinwardly from the upper housing portion. The lower baffle extendslaterally beyond the lower housing portion so that its periphery liesoutside this portion, but preferably terminates in spaced relation tothe skirt 22a, as shown. Upper baffle 26 may be smaller than lowerbaflie 23, and its corners may extend into the enlarged upper housingportion so as to be secured thereto as indicated previously. At leastthe bottom section of the upper housing portion is large enough toaccommodate the baffles. The upper baifle extends laterally beyond thecentral opening in baffle 28 an amount sufficient to ensure shielding ofthe ducts, but at least part of the periphery of the upper baflle isspaced from the inside of shield 22 so as to continue the air passageafforded by the opening in the lower bafiie and to allow rain to dripfrom the upper baffle onto the lower baflie. I

The upper surface of the baflles is preferably conoidal, which includesboth conical and spherical shapes. However, other surfaces shaped todirect water from the center toward the outer extremities of the bafilesmay be employed. For simplicity, the bafiies have been cut so as to havefour corners, but it will be evident that other outlines may beemployed. The baffles may be curved to the contour illustrated bycutting and dishing flat stock in suitable press as indicated in Figs.1-3. Alternatively, as shown in Fig. 4, each may be formed from twogenerally rectangular pieces 76 each having a substantiallysemi-circular cutout 71 along one side thereof, by mating thesemi-circular portions oppositely, deforming the fiat sheets into agenerally conical shape so that the straight edge portions adjoining thesemi-circular portions overlap, and securing such lapped portionstogether in any suitable way, as by riveting at the parts 72. This formof construction produces a baffle the sides 73 of which bow slightlyoutwardly at the center, while the overlapped sides also are not quitestraight, in plan view, but by virtue of the considerable projection ofthe bafile edges over the space between the housing 17 and the skirt22a, the rain and soot disposition are substantially as hereinafterdescribed. Each baflle may also be formed from a single more or lessS-sided flat sheet of material with a generally keyhole shaped slotdiverging toward one edge of the sheet. If the diverging straight edgesof the slot are drawn together and overlapped, the sheet will assume agenerally conical shape with the circular portion of the slot formingthe opening for flue 30 and with a generally square periphery in planview. lf the periphery of the flat sheet has straight sides to beginwith, the sides will be bowed outwardly when the bafiie is formed inthis manner. if it is desired to have straight sides (as seen in plan),the sides must be cut concavely before the bending process begins. Asthe sheet is bent, the corners formed by the intersecting sides willcurve downwardly, thereby making the corners the lowest portions of thebaflies, as shown in Fig. 1.

With the chimney top assembled as illustrated, the upper extremity offlue 30 will be protected from rain by rain cap 24 and the cooperatinglip 68 of shield 22. The upper extremities of ducts 40 and 42 willsimilarly be protected by balfles 26 and 28. The side surfaces of shield22 and lower housing portion 17 serve to prevent rain from entering theflue and ducts from a sideward direction. Rain which strikes the uppersurface of rain cap 24 runs toward the edges of the rain cap by virtueof the contour of its upper surface and drips onto baflle 26. Rain anddrip striking the upper surface of baffle 26 run toward the corners ofthe baffle since, as described above, the corners are preferably thelowest points on the baffle surface. If the corners of baflie 26 aredrawn up snugly against the inside of shield 22 as shown in Fig. 2, therain will drip from baffle 26 to baflie 28 when it reaches the shield.Any rain which strikes the upper surface of baflie 28 is similarlydirected toward its corners and drips therefrom onto the roof. Finally,any rain that runs down the inner wall of section 22a can drip therefromto the roof. It will thus be observed that the rain water is directed soas to drip onto the roof rather than to run down the outside of thehousing 16. In this manner any soot and ash picked up by the rain islargely prevented from staining the outside of the chimney top. Soot andash may collect on the rain cap, baffle and shield but will be preventedfrom entering the ends of ducts 40 and 42. The ducts will thereby bemaintained free of soot and ash deposits, which in the absence of suchprotection could seriously interfere with the free flow of air throughthe ducts.

As described in my aforesaid prior patent, in operation of the chimney,the hot flue gases in flue 30 causes a thermosyphonic flow of air inducts 40 and 42, with air passing downwardly from the atmosphere in duct42 and upward to the atmosphere in duct 40. The chimney top constructiondescribed does not interfere with the thermosyphonic circulation of airin ducts 40 and 42. In addition, in the form shown, the chimney topprovides for attic ventilation as set forth in my aforesaid patent, theattic air passing upward in the spaces between square collar 48. of theflashing and the circular area of the outer casing34. In summer, thisair will rise upwardly and exhaust through passages 44 and 46 in thechimney top, while in winter, when avoidance of condensation isparticularly desirable, the air may also pass downwardly into duct 42 byvirtue of the thermo-syphonic flow.

The chimney top may be installed quite simply. A rectangular hole of theproper size (which may be approximately 17" X 17") is located on and cutthrough the roof sheathing. Headers may be provided if necessary. Thelower inside edge of the upper flashing section 18 is aligned with theupper edge of the roof opening as illustrated in Fig. 2 at 69. The upperbrackets 54 (one one each side of the flashing) are arranged as in Fig.1 and screws are driven through the horizontal legs of the brackets intothe sheathing so as to secure the brackets and flashing to sheathing.Wooden blocking members may be employed to back up the sheathing so asto ensure that the brackets are tightly held. The bottom flashingsection is then slid inside and under the top section until its insidelower edge lines up a few inches above the lower edge of the roofopening. The collar portions will then overlap with the collar portionof the lower flashing section inside the corresponding collar portion ofthe upper flashing section so as to form collar 48. The chimney then maybe installed, sertion by sertion, until the flue and ducts extendthrough the hole in the roof. The chimney top housing 16 is cut to anappropriate length with its lower edges conforming to the pitch of theroof with the chimney housing vertical. The length of the housing isselected so that the top of the housing extends approximately 2 feetabove the ridge 12 of the roof when the housing is installed. Thehousing is tilted back toward the ridge and then lowered over theflashing so that the sides of the housing lie between the upper pair ofbrackets 54 and the collar 48. The housing is then brought to verticalposition so that the sides of the housing lie between the brackets andthe collar of the upper and lower flashing sections. The lower flashingsection is then drawn down the roof slope until its upper edge restsagainst the inside of the housing 16. The lower pair of brackets 54 isthen secured by placing the vertical legs of the brackets against thesides of housing 16 and driving screws into holes provided in the lowerlegs of the brackets through the flashing section 20, sheathing 14, andinto the rafters or blocking. Housing 16 is then secured to the verticallegs of brackets 54 by sheet metal screws which are driven through holesprovided in the vertical bracket legs. The telescoping flue section 36may then be in serted through the opening 47 at the top of shield 22,through baffles 26 and 28, and into lower flue section 38 until theflared end 64 of the upper flue section rests on baffle 26. The rain cap24 is then secured to the top of shield'22 as by bolts or screws. Thechimney top can be painted or pre-painted, or otherwise finished tobarmonize with the building design, and roofing material may then beinstalled in the conventional way so as to overlap the flashing sections18 and 20.

Any suitable materials may be chosen for the construction of the chimneytop and its components. For example, the smoke flue may be composed ofstainless steel, enameled steel or aluminized steel; the housing,shield, baffles, rain cap, etc. may be composed of aluminum, aluminizedsteel, or galvanized steel. While the outer casing has been illustratedas rectangular, it will be appreciated that a cylindrical, oval, orother convenient configuration may be employed. The relative proportionsof the parts of the chimney top may be varied within 6 wide limits solong as the dimensions are commensurate with the functions describedpreviously. The invention is also described in the Report on Fireplaceand Flue issued by the Underwriters Laboratories, Inc., miscellaneoushazard report 6018, July 14, 1954 (copy attached to and forming a partof the record in my application S. N. 479,131, filed December 31, 1954),which is herein incorporated by reference. Construction details anddimensions are 'set forth in said report, as well as test pro ceduresand results. v

A preferred form of the invention has been described and illustrated,but it is to be understood thatthe invention is not to be considered aslimited thereby, that changes may be made in the arrangement andproportion of parts, and that equivalents may be substituted withoutdeparting from the spirit and scope of the invention.

It is, therefore, to be understood that the exemplary embodiments areillustrative and not restrictive of the invention, the scope of which isdefined in the appended claims, and that all modifications that comewithin the meaning and range of equivalency of the claims are intendedto be included therein.

I claim as my invention:

1. In combination with a chimney flue, a chimney top comprising ahousing adapted to be mounted substantially upright above a roof and toenclose the end of said chimney flue, said housing comprising upper andlower tubular portions, means for supporting said upper portion inspaced relation to and above said lower portion, a rain cap mounted inthe upper portion of said housing above said flue end, said housinghaving an opening above said cap for egress of flue gas, and a bafflesupported by said housing below said rain cap, said baflle having acentral opening of a size sufficient to accommodate said flue and form apassage between said batflc and said flue, said baflle being positionedin spaced relation to and above the top edge of said lower portion ofsaid housing to provide an air passage between said battle and saidlower portion, said baffle extending laterally beyond the area of thelower portion, whereby rain water drips from the periphery of saidbaflie beyond the outside surface of the lower portion of said housing.

2. A combination in accordance with claim 1, including a second bafilearranged in said housing spaced above the first-mentioned baflle withsaid flue passing through said baffles in succession, said baflles eachhaving an upper surface which slopes downwardly from said flue towardthe baflle periphery, at least a portion of the periphery of each bafliebeing within and spaced from the inside of the upper portion of saidhousing, the periphery of each baffle being substantially polygonal, andthe corners of each baflle being the lower-most points thereon andextending laterally between adjacent corners of the other baflle.

3. A combination in accordance with claim 1, said baffle having adownwardly sloping surface with a polygonal periphery, the corners ofsaid baflie being the lowermost points thereon and extending laterallyfarthest outside the lower portion of said housing.

4. In combination with a chimney flue, a. chimney top comprising ahousing adapted to be mounted substantially upright above a roof and toenclose said chimney flue, said housing comprising a lower tubularportion terminating below the upper end of said flue and an uppertubular portion terminating above said flue end, means for supportingsaid upper portion in spaced relation to and above said lower portionwith the bottom edge of said upper portion extending laterally beyondand surrounding the top edge of said lower portion so as to define anair passage therewith, said upper portion having an opening at its top,a rain cap mounted in said upper portion below said opening and abovethe upper end of said flue, a first baffle through which said fluepasses mounted Within said upper portion below said rain cap andextending laterally in said upper portion, a second baffle through whichsaid flue passes mounted inside said upper housing portion below saidfirst bafile, at least a portion of the periphery of said first bafflebeing spaced from the inside of said upper portion and spaced inwardlyof the corresponding peripheral portion of the second baflle, wherebyrain water may drip therefrom onto said second baflie, and at least aportion of the periphery of said second baffle being spaced from theinside of said upper portion but extending laterally beyond the area ofthe lower portion, whereby rain water may drip from the periphery ofsaid second bafiie beyond the outside surface of the lower portion ofsaid housing.

5. A combination in accordance with claim 4, said second baflle havingan aperture forming an air path therethrough around said flue.

6. A combination in accordance with claim 4, said baifles being conoidaland having an upper surface sloping downward from said flue.

7. In combination with a thermo-syphonic chimney having a flue and apair of concentric ducts therearound and adapted to pass through a holein a roof with the outer duct spaced from the periphery of said hole, achimney top comprising a tubular housing adapted to be mounted uprighton said roof and to surround said flue and ducts but spaced therefrom,said housing having an opening at its lower end adapted to surround saidroof hole and an opening to the atmosphere at its upper end, a rain capmounted on said housing above the end of said flue and aligned with andspaced from said opening to the atmosphere, said rain cap extendinglaterally beyond said flue end so as to shield the latter, a firstbaffle mounted in and extending laterally in said housing, said fluepassing snugly through an aperture in said baffle, a second baiflemounted in said housing below said first baflle, said flue passingloosely through an aperture in 8 said second baflle, said housing havingan opening to the atmosphere below said second baflle and having an airpassage past said first bafi le near the periphery thereof.

8. A combination in accordance with claim 7, including flashing adaptedto be secured to said roof around said hole and having an upwardlyextending collar adapted to surround said hole and extend into saidhous- 9. In combination with a chimney flue, a chimney top comprising ahousing having an opening at its lower end to receive said chimney flueand an opening at its upper end to the atmosphere, said housingcomprising a lower tubular portion and an aligned upper tubular portion,means for supporting said upper portion in spaced relation to and abovesaid lower portion, the bottom edge of said upper portion being spacedlaterally outward from the top edge of said lower portion so as todefine an air passage therewith, and a baffle mounted in said upperportion extending in said upper portion laterally beyond said lowerportion and having an aperture to receive said flue, said flue includingan upper section sup ported by said baflie and telescoping with a lowersection, said upper flue section having an upper end of larger lateraldimension than said bafile aperture, whereby said upper flue section maybe suspended from said baffle.

References Cited in the file of this patent UTIITED STATES PATENTS98,800 Reynolds Jan. 11, 1870 2,437,771 Wait Mar. 16, 1948 2,634,720Thulman Apr. 14, 1953 2,687,127 Lefiler Aug. 24, 1954 2,713,301 McKannJuly 19, 1955 FOREIGN PATENTS 476,035 Italy Nov. 26, 1952

